1. Field of the Invention
This invention relates to the method of forming a barrier to seal off a remote chamber; specifically, for forming a gas-impermeable seal for firefighting in a confined space, such as a coal mine.
2. Description of Prior Art
Fighting a coal mine fire is dangerous and costly. Because the fire is typically in a confined space of the mine, there are numerous unsafe conditions including: mine subsidence, extreme heat from the fire, and explosive and noxious combustion gases. Specialized safety and firefighting equipment adapted for the unsafe conditions is needed to safely fight the fire. In addition, the area involved in a fire is normally sealed off from non-involved areas by the placement of barriers. In many cases, this involves personnel entering the mine to erect a brattice or other sealing device; exposing them to unsafe conditions. Attempts have been made to improve and make safer the conditions for fighting fires in coal mines and similar confined spaces. Such attempts include procedures for remotely sealing the involved area and remotely fighting fires in confined spaces so as to avoid exposing personnel to the dangers involved with fire fighting in confined or enclosed spaces.
One procedure for remotely fighting fires involve pumping concrete through a borehole to smother the fire. A problem with this method is that the borehole is filled with concrete, ending the usefulness of the borehole.
Another method for remotely fighting fires is to inject a fire extinguishing foam as disclosed in U.S. Pat. Nos. 7,096,965 (the '965 patent) issued on Aug. 29, 2006, and 7,104,336 (the '336 patent) issued on Sep. 12, 2006, both to the present inventor. In the '965 and '336 patents, an initial step involved in fighting fires is to seal off the area of the mine on fire to prevent the spread of the fire and to control the disposition of the fire suppressant. This method can utilize boreholes to deliver the fire extinguishing foam.
With a typical borehole around a hundred feet to thousands of feet deep, it is expensive to drill, with a typical borehole costing approximately $100,000. Boreholes are even more expensive to fill with concrete, costing approximately $250,000. Thus, there is a need for remotely fighting fires in a coal mine by using the previously drilled borehole both to remotely prepare a barrier and to deliver a fire extinguishing material.